Speed and altitude responsive control for aircraft heaters



SPEED ANIS ALTITUDE RESPONSIVE April 5 1949- E 'J. DILLMAN 2,466,582

I CONTROL FOR AIRCRAFT HEATERS Filed ept. 27, 1945 5 Sheets-Sheet l INVENTOR (WW7. @MM BY 6224M W J -v ATTORNEY 5 Sheetg-Sheet 2 EJJ. DILLMAN SPEED AND ALTITUDE RESPONSIVE CONTROL FOR AIRCRAFT HEATERS m M T Y. N O E E .N w VK M T M m 5 Y w E vs J /8 9 e III 5 5 A F m n, w IRI |c RS m E E w Ill H! W R W 0 U d 5 5 E 3 v E S R r0 R E U R 5 n w a m m R l m P T E m 4 l 2 y 7. m 5 0 3 mwIuz 'umDmmuma Pa -.50

April E. J. DILLMAN 2,466,582

SPEED AND ALTITUDE RESPONSIVE CONTROL FOR AIRCRAFT HEATERS 5 Sheets-Sheet 5 Filed Sept. 27, 1943 INVENTOR ATTORNEY I J. SPEED AND ALTITUDE RESPONSIYE CONTROL. FOR AIRCRAFT HEATERS E. DILLMAN 5 Sheets-Sheet 5 April 5, 1949.

Filed Sept. 27, 1943 hum boat-51 0 2 4 6 8 l M M w w wI mmzozTmmnmmmma uimlamozz SEA LEVEL 2.0 5.0 STATlC PRESSURE 0F COMBUSTION AIR-INCHES WATER INVENTOR Mr. M

FIG-l5 M ATTORNEY UNITED STATES PATENT OFFICE SPEED AND ALTITUDE RESPONSIVE CON- TROL FOR AIRCRAFT HEATERS Earnest J. Dillman, Detroit, Mich., assignor to Detroit Lubricator Company, Detroit, Mich, a corporation of Michigan Application September 27,1943, Serial No. 503,883

21 Claims. 1

This invention relates to new and useful im- Drovements in heating apparatus and more par ticularly to a method and apparatus or device for controlling the combustible mixture to be supplied to the combustion chamber of the heating apparatus, I

An object of the invention is to provide a method of maintaining a substantially constant heat output of aircraft carried heating apparatus.

Another object is to provide means for maintaining the weight of combustion supporting air in accordance with the weight of fuel supplied to the combustion chamber, irrespective of any substantial change in barometric pressure.

Another object is to provide means to maintain the weight of the air supplied to the combustion chamber from the exterior of the aircraft substantially constant per unit of time, irrespective of change in aircraft speed.

Another object is to provide means to heat the combustion supporting air so that the Weight of the supplied air will be substantially unaffected by change in atmospheric temperature external of the aircraft.

In addition to the foregoing objects, other objects will be apparent from the following specification.

The invention consists in the novel method and the novel apparatus and cooperative relation of parts to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of this specification, there are fully and clearly illustrated several preferred embodiments of the invention and certain modifications of the same, in which drawings- Figure 1 is a top plan view of a control device or apparatus for regulating the combustion supporting air and embodying the invention;

Fig. 2 is a view in section on the line 2-2 of Fig. 3 is a view in section on the line 3-3 of Fig. 2;

Fig. 4 is a detail view in section on the line 4-4 of Fi 1;

Fig. 5 is a view in section on the line 55 of Fig. 2;

Fig. 6 is a view in section on the line 6-3 of Fi Fig. 7 is a view in section on the line 1-4 of Fig. 2;

Fig. 8 is an enlarged detail view in section on the line 88 of Fig. 3;

Fig. 9 is a diagrammatic view of an aircraft carried heating apparatus having the control device of Figs. 1 to 8 operatively connected thereto;

Fig. 10 is a detail view in section of a portion of the device of Fig, 6 and showing a modification for accomplishing a closercontrol of the weight ofcombustion air throughout the complete range of aircraft altitudes;

Fig. 11 is a detail view partly in section and partly diagrammatic showing means for heating certain of the operating mechanism of the control device;

Fig. 12 is a detail view partly diagrammatic and showing another way of heatin the control device;

Fig. 13 is a view in vertical central section of a control device similar to that of Figs. 1 to 8 but accomplishing the novel method of air control by means of a single barometric pressure responsive element;

Fig. 14 is a view in vertical central section of another form of control device for performing the method of this invention but which functions to maintain the weight of supplied air more nearly at the theoretical value throughout the range of aircraft altitudes;

Fig. 15 is a chart showing graphically the operation of certain of the foregoing control devices, and

Fig. 16 is a chart showing graphically the operation of the control devices at a given or constant aircraft altitude,

Referring to the drawings by characters of reference in Figs. 1 to 9, the numeral I designates a control device having a casing 2 with top and bottom hollow members 3, 4 providing chambers 5, 6 respectively separated by a pressure sensitive member or diaphragm 1, preferably of a cloth and rubber composition which is clamped and sealed at its periphery between the members 3 and 4 by studs or bolts 8 which also-clamp these top and bottom members together. The top member 3 has a hollow extension 9 projecting beyond the periphery of the diaphragm l and the member 4 and which has a downward facing opening i0. Extending from the periphery of the bottom member 4 at one side of the extension 9 there is a plate like supporting shelf H, see Figs. 4 and 7. Secured to the under side of the shelf H and of the bottom member 4 there is a pad or plate l'2 of heat insulating material to the under face of which there is clamped by a pair of screws l3 an airflow conduit member or tubular valve casing M which carries at one side and beneath the extension 9, a casing portion [5 having an upwardly opening aperture l6 registering with type.

somewhat for variations in "air pressure.

the opening ID. The joint between the casing member 3 and the portion I5 is sealed around the registering apertures ID and I6 by a gasket II.

The conduit member l4 has opposite horizontally positioned shaft receiving bosses l8, I9, the boss I 9 extending into the casing portion |5. Through'the'bosses I8, [9 thereere'horiz'ontal aligned apertures 20,"2| respectively'intowhich extend the opposite ends of a valve supporting shaft 22 having its end portions of reduced diameter and journaled in supportingzplates 23, 24 carried by the bosses l8, l9 respectively. The plate 23 is in a form of a cap member-such as to seal the shaft aperture-'20. The end-pOrti n 25 which extends through the bearing plate 24 projects into the casing portion l5 and has-rigidly fixed thereon a crankarm'26. Between the opposite internal walls of the conduitmember I4, the shaft 22 is of semi-circular cross section and hasclamped to its flat diametral face an air flow .controlling'valve 21 of the butterfly The'valve 21 is 'of oval outline so that it will conform to and close 'ofiflow through the conduit member |,4' with less than 90 "rotation.

Thelea'din'g and trailing end "edges offthe-valve 21 are bevelled, as at 28, 29 're'spectively,"s'othat the periphery of the valvewilrfit'theinternal wall of the ,conduit'member |4 when the 'valve member isclosed. This arrangement of the valve '21 results in the air pressure exerting aislightly unbalanced closing force so as to compensate The valve2'l isrestra'ined against movement beyond full open position by a stop member or'pin 29 4 35 heads'such'that it acts to expand the bellows which extends into the conduit'l4 forengage- 'mentby the valve 21.

"'Pivotally secured tothe free'endof the arm 26 which extends downward from the shaft '22, there is a link or thrust member 30. "Iheangle "of the arm'26 is such that, with the valve-2'1 in horizontal wide open position, it has'adecfeler- "ated movement toward closed position for-equal increments of' upward movement of the-link"30. Also the link 30 acts through an increasing lever arm as the valve moves toward closed' 'position, so thatwith a constant upward'force onthe link 3ll'an increa'sing'closing force will beexei-ted on the valve 21. The link 30 extends upward through the'apertures l6 and "land has its free end pivotally secured toanactuatiriglever 3| which is positioned within the chamberi and extends across the-diaphragm I. Theend -'-portion of the lever 3| within the chamber '5'and *overlying the center of the diaphragm I is a substantially rectangular framework having side frame members 32,-33'rigidlyjoine'd together and fulcrumed on aligned inwardly extending bearing pins" 34,"35 respectively which are adjustably supported in'bosses 3'6, =31 carried by'the top *member-Q. Thebearing pins '34, 35- are preferably shouldered to accurately-locate the lever "3| transversely of the casing. 'Thediaphragm I has a reinforcing and-supporting plate '38 to which'is secured an inverted U-shapedbracket 39 extending transverse to the leve'r members 32, 33 and across the 'mid p'oint of the diaphragm '1, The side members of the bracket fit between the frame members '32, '33. The bracket beds-pivotally securedto the lever 3| by means of a shaft or pivot'pin 40 extending "through aligned apertures-in the "frame members "32, 33 and the side membersjof thebracke't-39. Secured 'to'the cross member or baseof the bracket-39 there is a guide rod 4| extending'upwardlyand having a ball type end 'slidablyguided andfitfor connection to a source of pressure to act on "the topxface'sof the diaphragm l for a purpose to be described.

Overly-mg the lever member 33 there is an expansible-contractible hollow member such as l5 -a metal-bellows which is evacuated of air and hermetically sealed. The bellows upper end wall orheadlfi'has' asupporting stem or rod 41 adjustably-screw threaded through a cover plate 48 closing and sealing a top wall aperture in the 20 I top member 3. A lock nut 49 containing a packing'material" clamps the stem 41 in position and seals the aperture through the member '48. The 'lower bellows end or'hea'd '50 carries a'tubular guide and socket member 5| which extends up- 25 ward'into'thebellows '45. Seating against the upper inner end wall of the guide member 5| there is a force transmitting post or thrust mem- "ber 52 which is slotted at its lower end to strad- V dle the lever member ,33 to which the thrust 30 member'52 is pivotally secured by a bearing pin "53. Within the bellows 45 there is a helical coil spring which is held under compression between'the'bello'ws heads46 and'50 and which exerts ,aforce'relative'to the area of the bellows Thef upper end wall or head "56 of bellows 55 carries a'stem or supporting rod' 51 which-is adjustably screw threaded through an aperture in the hover-member 48 and which is locked in adjusted position by a combined sealing and lock "nut'58. The lower end wall-or head 59 of bellows '55 carries a combined guide and thrust transmitting socket member 60 which extends upward into the'bellows and has its upper end oo'oper ablawith the'head 56 to limit contraction "of',the".bellows 55. Surrounding the member and'held under compression between the heads 56 and 59 there is a helical coil spring 6| which, upon decrease of airpressure'in chamber 5 and around the"bellows-55, s'erveslto-expand the bel- 60 lows and "move the head 59 downward. The socket member 60 receives a post or, thrust member 62 which has its upper end engageable by the end wall of the socket member 60 to transmit downward force and movement of the "65 spring 6| to the'lever member32, the lower end of the thrust member 62 being slotted to straddl'ethemember '32 and being pivotally secured thereto by a bearing pin 63. The bellows 45 and -55are positioned between the diaphragm connection to the lever 3| and its fulcrum, the bel- "lows '45'being positioned to act on the lever 3| more closely to its fulcrum than the bellows 55, the relative positions being shown in Fig. 5. I Referring to Fig. 9, 64 designates thefuslage 15 *or abo'dy portion of-anaircraft having a space 65 therein to be heated. Either within this space 65 or in a separate space there is a heating apparatus having a combustion chamber 66 with a surrounding air heating chamber 61 which has an inlet duct 68 for air to be heated and an outlet duct 69 for delivery of the heated air to the space 65. The combustion chamber 66 is supplied with a combustible mixture of air and fuel by a mixing member which is preferably a baffle of ceramic or other porous material capable of capillary action. The member 19 has its lower end portion positioned in a fuel cup or chamber 1| which is supplied with liquid fuel from a tank or the like (not shown) by a pump 12 having high andlow rates of fuel feed. The member 19 has its lower half shielded by a partition or baflie 13 and has a plurality of air fiow ports or orifices 14 through its upper half or portion. The member 16 and baflie 13 form the combustion chamber wall of a static air pressure or plenum chamber 15 which is supplied with combustion supporting air through a conduit or duct 16. The combustion chamber 66 has an outlet conduit or duct 11 leading to the exterior of the aircraft for discharging the products of combustion to atmosphere from the chamber 66. The conduit 16 preferably has a portion 18 which extends in heat exchange relation with the outlet duct 11, the inlet to the conduit 16 opening to the exterior of the aircraft and having an inlet, as at 19, so that atmospheric air is supplied to the conduit 15 and chamber 15 by the movement of the aircraft in flight. The conduit 16 is also supplied with air from a branch conduit 86 connected to the outlet of a fan or blower 8| driven by an electric motor 82 and which supplies air to the chamber 15 when the aircraft is not in flight or its air speed is below a predetermined minimum. The pump 12 is driven by an electric motor 83 supplied with current through a low speed resistance 84 or a high speed resistance 85. The resistance 84 is connected in parallel circuit with the blower motor 82 from a common lead wire 88 connected to one pole 81 of a double throw switch 88. The switch arm 89 of the switch 88 normally engages the contact or pole 81 and is connected by a lead wire 90 to a control switch 9| in the lead wire from the current supply source 92 such as a battery, for the motors 82 and 83. The switch 88 is controlled by the air pressure in the conduit 16 and has a pressure sensitive operating member 93 which, upon predetermined conduit air pressure moves the switch arm 89 out of contact with the pole 81 and into engagement with a contact or pole 94 which is electrically connected to the high speed resistor 85. Intercalated in the conduit 16 adjacent the chamber 15 is the conduit member M such that the valve 21 controls the air pressure in the chamber 15. The inlet port 43 of chamber 6 is connected by a duct or pipe 95 to the chamber 15 so that the diaphragm 1 is subjected on its under side to the pressure in chamber 15 and in the conduit 16 on the outlet side or posterior to the valve 21. The port 44 which opens into the chamber 5 is connected by a duct or pipe 96 to the combustion chamber outlet duct 11, as at 91. The operation of the control device of Figs. 1 to 8 and the method of control accomplished thereby is as follows:

The bellows 45 is adjusted by the supporting member 41 so that at a known barometer reading with the aircraft on the ground, the static pressure in the plenum chamber 15 will be at the desired value to provide, with the pressure drop through the orifices 14, the desired ratio of air to fuel in the combustion chamber 66 for eificient combustion when the pump 12 is delivering fuel to the container 1| at its high constant speed operation. Referring to Fig. 15 the dotted line curve designated a shows graphically throughout the range of present aircraft altitudes the theoretically desired air pressure in chamber 15 to maintain a constant weight of air flow through orifices 14 per unit of time in order to maintain for all aircraft altitudes the desired fuel air ratio for eflicient combustion and to maintain a substantially constant heat output by the heating apparatus. The member 16 functions automatically with the maintenance of a constant liquid level in or rate of supply to the container 1| to supply fuel at a substantially constant rate to the air passing through the orifices 14. Referring again to Fig. 15 it will be noted that the bellows is adjusted so that the spring 54 will, at sea level, position the valve 21 to provide in the chamber 15 a static pressure of about seven and one-half tenths (.75) inch of water, as indicated by the full line curve designated 19, the bellows area, the force of spring 54, and the lever mechanism which operates valve 21 being so proportioned as to move the valve 21 to provide in chamber 15 the static pressures shown by this curve b at any constant aircraft air speed. The curve I) closely approximates the theoretical curve a up to an altitude of about 25,000feet above sea level and throughout this range of altitudes the bellows 45 controls the valve 21. The bellows 55 is adjusted by stem 51 so that when the pressure in chamber 5 decreases to about eleven (11) inches of mercury, corr spending to 25,000 feet altitude, the end wall of member will engage the thrust member 62 under the force of spring 6| andfor any further increase in aircraft altitude the spring 6| will act upon the lever 3| to move the valve 21.toward open position in conjunction with the force of the spring 54 so that the static pressure in the chamber 15 will be held on the curve 0 of Fig. 15, in order to maintain the weight of air supplied to the combustion chamber 66 substantially constant.

Assuming now that the aircraft is on the ground and it is desired to supply heat to the space 85, the switch 8| is closed, which will place the blower 8| inoperation and also the pump 12 at its low speed. Any suitable means may be employed to ignite the combustible mixture discharging into the combustion chamber 65. The pressure created by the blower 8| is insufficient to operate the valve 21 which will remain in its wide open position. As the aircraft takes off and gathers speed, pressure will build up in the conduit 16 and when a predetermined air speed is reached such that an increase in fuel should be provided and can be burned efficiently with the additional air due to the increased speed,

then the pressure switch 83 will be actuated .to break circuit at contact 81 and to make circuit at contact 64,'thus cutting out the blower Bi and supplying the pump motor 83 with current through the high speed resistance 65. This air pressure in conduit 16 at which switch 88 is actuated to stop the blower 6| is the pressure at which the diaphragm 1. will throttle the valve 21 to maintain the pressure in the chamber 15 substantially constant irrespective of change in the air speed of the aircraft for any given aircraft altitude. In Fig. 16 the operation of valve 21 by the diaphragm 1 is graphically shown for low altitude flight corresponding to about 29.7 inches of mercury. The static pressure in chamwere and 5 acting :on :the funder sideof the 'rdiaphragm will more accurately throttle the valve -27 lfthezpressure in chamber 5 acting on 'the topface of the" diapina'gm -'-'I is'varie'd in accordance'withor: is thezpressure existing inthe comaircraft has reached "an altitude of about-25,000

feet;thenthebelldwshead member '50 will en- :gage the :thrust member 62 and'the spring 61 will-act with the spring 54in opposition to'the :pressure in chamber fi to'throttle the valve 21 to 'mainta'in the static pressure in "chamber 15 on the curve 0 of Fig. 15.

"Referring to Fig. the thrustniemberfl is provided with: ashoulder "I 00 I on which is sup- ;ported a helical coil compression spring --IOI "which, :when inert, has its free endspaced from the end wall :of the socketcin bellows: head member-60. 'This spring functions to maintain the staticpressure in chamber 75- more nearly at the theoretically desired-pressures of curve a between aircraft altitudes of about 20,000 feet' and 27,000 'feet, .asin'di'cated by the dashdotline d, "Fig. 1-5. When the pressure in chamber 5 has'decreased to .about fourteen'ili) inches of mercury, then the 'socket end'avall in member 50-will engage the f free end ofuspring:I II I,and' as the pressure 'continuesito 'decreasewith increasing altitude, the spring I 0I will befcompressed, thereby exerting "with an 'increasing force the I force of spring '6 I -upon the thrust'member IiZ. When thepressure in chamber 5 has decreased to about ten(l'0) .inches of mercury, then the socket end wall of member -60 will have collapsed spring IOI sumcientiy to bring 'thesocket'end wall into positive 'engagement with the thrust member '62 so that the operation of the spring "fil'for'all further increases of altitude functions as above'described to maintain the static pressure in "chamber'15 on the curve 0. 'It will thus be noted that the modificatlon in" Fig. lflprovides for a'three stage operation,"accomplishing a closer control of the valve 21.

InFig. 11 there is shown means'for heating the valve operating mechanism in order to overcome a decrease in sensitivity of the parts at extreme- 1y low temperatures encountered in high altitudes. The casing portion I5 is-provided' with a calibrated inlet port I05 which is connected by a tube or conduit I06 to the heating chamber outlet so that heated air is supplied tothe chamber 5 of the'control device and particularly to the casing portion I5 which is at the air inlet conduit I4.

In Fig. 1 2 there is showna 'modification'of the heating-means of Fig. 11. Here the heated air is not dischargedinto the icasing 2 but is discharged over the conduit and scasing portion from the open end of a'duct I I0"which isconnected to'the air heating chamberIiI.

In Fig. 13 there 'isshown another-form of control :device I I in whichthe valve containing-conduitportion to be intercalated in the conduit "I0 is designated II5. The'conduit portion II52is elongated to underlie the diaphragm supporting casing IIIi containing a pressure chamber I-I'I 'whichis in communication with the interior of the conduit portion II5 through apart I I8. Positioned in the conduit portion or member '5 ahead of or-on the inlet side of the port H8 is the air flow controlling valve I I 9 similar to valve -2'I.

The chamber III is'closed and sealed'by a pressure sensitive member or diaphragm I20 having'a thrust member I2I similar to bracket -39-which is pivotally connected by a pin I22 to a valve operating lever I I23 extending-across the diaphragm -I20. The lever I23 is fulcrumed on a shaft or bearing pin 124 carried by the'casin'g II-Ii. The free end ofthe lever I23 is connected by a link or-thrustmember I25 to acrank arm I26 rlgidlysecured to'thevalve supporting shaft I21. The thrust member I 2| is guided by a: guide pin I28 reciprocal'in'a sleevemember 129 carriedby a housing I'30 secured to and supported on thecasing IIB. Positioned in the housing I30 there is 'a barometric operating element I3I.

preferably an 'expansible contractible hollow member .such as a metal bellows which is evacuated of air and hermetically sealed and contains a helical-coil compression spring I32.

"The upper head or endwall I33 of the element I3I has a stem or supporting post I34 adjustably screw threaded through the top walliof ithe'housing I 30. The'lower'end wallorhead I35ofithe element I3I 11s .in the form of an inverted .cup fexten'dingiupward into the element I3I.

The element I3I overlies the lever I23and concentric "with-stem I 3lthere isiathrust memberfli :piv-

otally' connected to the lever I23 :and extending 'upward therefrom. Supported on the upperren'd of the member I 35 there is 'a spring supporting 40 portion I 38rengageable by the end wall I35. Positioned withinand between'the end wall I 35 and and abutment'me'mber I31 having its peripheral the supporting member I31 there are a plurality of 'nested helical coil springs I39, I40 and I which. are of different lengths. and HI are of such inert length that there is movement of the'head I35 againstthe force of The springs I40 spring I39 prior to engagement ofthe head with sprlngI I0, and there is compression of spring Why the head I35 prior to engagement of the head I35 with the spring I5 I. The spacing ofthe sprlng III from the head I35 is-also such that it will be compressed by the'head I35 prior to engagement of the head I35 with the peripheral supporting member 'portion I38. Adjustable screw stop I42 is carried by the lever I23 and is cooperable with the casing I I6 to limit the movement of ,the valve IIS to wide open horizontal position.

The operation of the control device of this Fig.

13 'wil1-be apparent from the foregoing description of Figs. 1 to "9, together with the following:

The diaphragm I20 will'function to control the valve II9 in the same manner as the control of -valve21- by diaphragm I, although it will be noted that the housing I30 is open to atmosphere'and therefore the compensating efiect of the pressure in the discharge duct from the combustion chamber 56 is not provided, but modulation of valve -I I9 will be sufilciently accurate for good control of the airflow. As the aircraft gains in altitude the element I3I will expand, permitting spring I32 to act throughthe spring I39 against lever 123 inopposition to the pressure in diaphragm chamber I I1. Springs B and HI will be picked up or engaged by the head l35'as the aircraft altitude increases, thereby giving curved line changes of static pressure increase similar to the curve line 01 as distinguished from the straight line curves 1) and c. When the aircraft altitude has increased sufiiciently to bring the head I35 into engagement with the supporting member portion I38, then the spring I32 will act in the same manner as spring 54 of Figs. 1 to 8 and provide a straight line curve of static pressure increase in the air supply chamber 75.

In Fig. 14 the control device shown in Fig. 13 is modified to include three barometric operating elements I50, II and I52 in lieu of the single element I3I of Fig. 13. The elements I50, I5I and I52 are expansible, contractible hollow members such as metal bellows which have been evacuated of air and hermetically sealed and each of which contains a helical coil compression spring similar to the elements in Figs. 1 to 8. The element I50 is carried by a supporting member or stem I 53 adjustably screw threaded in the top wall of the housing I54 and is pivotally connected as at H555 to the lever I23 so that upon decrease of the atmospheric pressure the element I50 will tend to expand under the force of its contained spring acting to move the lever I23 downward and the valve I I9 toward open position to maintain the static pressure in the chamber I5 on the curve I) of Fig. 15. The element I 5| is adjustably supported in the top wall of the housing I 54 by a stem or supporting member I56 and is spaced from engagement with the lever I23 as at I51 so that it will come into play to exert force on the lever I23 in conjunction with the element I50 at say fourteen (14) inches of mercury or about 20,000 feet altitude so that the static pressure in chamber '15 will follow the curve e, Fig. 15, which more closely approximates the curve portion a between fourteen (14) inches and ten (10) inches of mercury than do the combined curves b and c. When the aircraft altitude exceeds 27,000 feet at a mercury pressure of say ten (10) inches, then the element I52, adjustably supported by the stem or supporting member I58, will have expanded to take up its lost motion, as at I59, so that its contained spring will be acting against the lever I23 in conjunction with the springs in the elements I50 and I5I and throttle the valve H9 to maintain the static pressure in the chamber on the curve 0. It will be apparent that, if desired, another or fourth barometric element could be provided to become effective at about six (6) inches of mercury pressure to establish a new curve conforming more accurately to the curve a than does the curve 0. As the operation of the control device of Fig. 14 is otherwise the same as that of Fig. 13, it is believed that no further description of this figure is necessary to a full and complete understanding of the same.

What is claimed and is desired to be secured by Letters Patent of the United States is:

1. In an aircraft carried heating apparatus having a combustion chamber air supply duct leading to the exterior of and having its inlet directed upstream of the aircraft, a control device comprising an air flow regulating valve in the air supply duct, means responsive to aircraft speed created pressure changes in said duct on the outlet side of said valve and operatively connected to said valve to move said valve toward closed position with pressure increase, and means responsive to change in aircraft altitude and operatively connected to said valve-to move said 10 valve toward open position with increase of altitude.

2. In an aircraft carried heating apparatus having a combustion chamber outlet duct leading to the exterior of the aircraft and having a combustion chamber air supply duct leading to the exterior of and directed upstream of the aircraft, a control device comprising an air flow regulating means for the air supply duct, means responsive to the differential of aircraft speed created pressure in said supply duct on the outlet side of said regulating means and the pressure in the combustion chamber outlet duct, means operatively connecting said responsive means to said regulating means to control said regulating means to reduce the effective flow area of said duct in accordance with increase in the differential of such pressures, and means responsive to change in altitude of the aircraft and controlling said regulating means in opposition to said differential responsive means.

3. In an aircraft carried heating apparatus, means forming a combustion chamber having an outlet duct discharging exteriorly of the aircraft and having an atmospheric air inlet duct leading from the exterior of and directed upstream of the aircraft, means to supply fuel to said chamber, said inlet duct having means forming an air supply chamber discharging through one or more orifices into said combustion chamber, air flow regulating means in said duct anterior to said supply chamber, a casing having a pressure chamber, pressure sensitive means responsive to aircraft speed created air pressure in said pressure chamber, a conduit establishing communication between said pressure chamber and said supply chamber, means operatively connecting said regulating means to said sensitive means to reduce the air supply with increase in aircraft speed, means responsive to aircraft altitude, and means operatively connecting said altitude responsive means to said regulating means to increase the air supply with increase in altitude in opposition to said sensitive means.

4. In an aircraft carried heating apparatus,.

means forming a combustion chamber having an outlet duct discharging exteriorly of the aircraft and having an atmospheric air inlet duct leading from the exterior of and directed upstream of the aircraft, means to supply fuel to said chamber, said inlet duct having means forming an air supply chamber discharging through one or more orifices into said combustion chamber, air flow regulating means in said duct anterior to said supply chamber, a casing having a pressure chamber, pressure sensitive means having one side subject to aircraft speed created pressure in said pressure chamber, a conduit establishing communication between said pressure chamber and said supply chamber, said casing having a second pressure chamber, said sensitive means having its other side subject to pressure in said second pressure chamber, a conduit establishing communication between said second pressure chamber and said outlet duct, means operatively connecting said regulating means to said sensitive means to decrease the elfective flow area of said duct as aircraft air speed increases, means responsive to aircraft altitude, and means operatively connecting said altitude responsive means to said regulating means to increase the effective flow area of said duct as aircraft altitude increases.

5. In an aircraft carried heating apparatus, means forming a combustion chamber, a casing having a pressure chamber,- a pressuresensitive member responsive to aircraft speed createdair pressurechanges in said chamber, an air flow conduitextending from the exterior of and hav ingits inlet directedupstream ofthe aircraft forsupplying combustion air to the combustion chamber of the heating apparatus, a valve controllingfiow through said conduit, means operatively connecting said valve to said sensitive mem-- ber to move said valve toward closed position upon'increase of aircraft speed created air pressure in said pressure chamber, an air pressure transmitting duct connecting said pressure chamber to said conduit on the outlet side of saidvalve, and-means responsive to altitude changes andoperatively connected-to saidvalveto move saidvalve-toward open positionwithincrease in aircraft altitude.

6 Inan aircraft carried heating apparatus, a casing having a pressure chamber; a pressure sensitive member responsive to aircraft speed created air pressure changes in said chamber, an air flow conduit extending from the exterior of and having its inlet directed upstream of the aircraft for-supplying combustion air tothe heating apparatus, a valve controlling flow through saidconduit, means operatively connecting said valve to said sensitive member to move said valve toward closed position upon increase of aircraft speed created air pressure in said pressure chamber, an air pressure transmitting duct for connecting said pressure chamber to said conduit on the outlet side of said valve, means responsive to altitude changes-and operatively connected to said valve to move said valve toward open position at a predetermined rate in accordance withincrease in aircraft altitude throughout an initial range of altitude increase, andmeans responsive to altitude changes and operatively connectedto said valve to move said valve towardopen position at a predetermined increased rate in accordance with increase in aircraft altitude throughout a higher range of altitude increase.

7. In an aircraft carried heating apparatus having a combustion chamber. andhaving .an air supply conduit leading to said combustion .cham.-, her. from the exterior of the aircraft, said conduit. having its inlet directed. toward the direction of aircraft travel, a control device comprising a sealed casing, a diaphragm separating the in? terior of said casing into two pressure.chambers,. a. butterfly type valve in and controlling flow through said conduit, saidcasing having an'air inlet to one of said chambers and communicating, with said conduit on the outletsideof saidvalve to subject said diaphragm to aircraft speedlcreated air pressure, saidcasing having a port open? ing into the other of said chambers and communicating with the outlet of. the combustion chamber of the heating apparatus, lever mechanism in said other chamber and operatively connecting said diaphragm to said valve to move said valve toward closed position upon increase of air-- craft speed created air pressure in said one chamber, an evacuated hermetically sealed metalbellows in said other chamber, a-helical coil spring in and tending to expandrsaid bellows,,said.bellows, being interposed between said casing and said lever mechanism and acting on said lever mech anism upon increase of aircraft altitude; to move said. valve toward open position, an evacuated; hermetically sealed metal bellows in, saidotherv chamber and of greater area than said first-.- named bellows, a helical coil spring in and tending to, expand said second-named bellows, and

1 to move-saidvalve toward open position;

8'. In anaircraft carried heating apparatus having a combustion chamber and having an .air: supply conduit leading to said combustion chamher from the exterior of the aircraft, said conduit, having its'inlet directed toward the direction-of. aircraft travel, acontrol, device comprising a, sealed casing, a diaphragmseparating the interior of said casing into two pressure chambers; a butterfly type valve in and controlling flow throughsaid conduit, said casing having an air:-

inletto one of said chambers andzcommunicatinsa with saidconduit omthe outletsidelof said valve" to subjectzrsaid. diaphragm to aircraft. speedcreated air pressure, saidcasinghaving a port'openzing into theother of said chambersand communicatingrwiththe combustion chamber outlet of' the heating. apparatus,,lever. mechanism in, saidrother chamberand operatively connecting; saidxdiaphragm to saidlvalve-to move said valve. towardclosedv position; upon increase of pressure; in saidgone. chamberymeans. to heatsaid lever mechanism and: the; bearings forsaid valve,,an evacuated: hermetically sealed metal bellows, in, saidnother: chamber,.a helical. coil spring inland-1 tending to expand saidbellows, said bellows being interposed: between said; casing and said lever mechanism and acting on, said lever mechanism; upon, increase of aircraft altitude to move-said, valve toward open position, an,evacuated hermetically; sealed, metal bellows insaid other chamberand of greater area than said first, named-bellows, a helical coil spring inand-tend-- ingto expandisaid second-named bellows, anda. thrust. member. providing a lost-motion connec--- tionsbetween said second-named bellows and said; lever: mechanism. and acting, upon altitude increase, above a. predetermined aircraft altitude to; move said ,valve toward open position.

9. In. an. aircraft carried heating apparatus having a combustion chamber and having an air supply, conduitleading to said combustion chain,- berifrom the exterior ofthe aircraft, said conduit. having; its .inletdirected toward the direction-of aircraft travel, a, control device comprising a sealed casing, a diaphragm, separating the interior of said easing into two pressure chambers, a butterfly type valve in and controlling flow throughsaidiconduit, said casing having an air inlet to one of said chambers and communicating with. saidzconduit on the outlet side of said valve, to, subject said diaphragm to aircraft speed created-air: pressure,,said casing having alport opening into the other of said chambers and com-' municating withthe combustion chamber outlet of the heatingapparatus, lever mechanismlin. said other chamber and operatively-connectiug said: diphrag-m to said valve to move, said-valve toward closed position upon increase of pressure in' said one chamber, a plurality of evacuated hermetically sealed expansible contractible hollow-:members, eachpf said hollow members containing; a, spring tending to expand its member, each of said hollow members being positioned to. act onsaid lever mechanism, one: of said. ho1lowmembers being positioned adjacent; the fulcrum of; and acting onsaid lever mechanism at low altitudes,v and another of; saidv hollow members being; spacedfurtheraway, from the fulcrum of and being, spaced.- from engagement with said lever mechanism: so that saidiother'hollow mem- 13 her engages and acts on said lever mechanism at higher altitudes, said springs tending to move said valve toward open position upon reduction of barometric pressure.

10. In an aircraft carried heating apparatus, means forming a combustion chamber, a casing, a pressure sensitive member responsive to aircraft speed created air pressure changes in said casing, a conduit extending from the exterior of and having its inlet directed upstream of the aircraft for supplying combustion supporting air to the combustion chamber of the heating apparatus, a butterfly type valve controlling flow through said conduit, lever mechanism operatively connecting said sensitive member to said valve to move said valve toward closed position upon aircraft speed created air pressure increase in said casing, said casing having an opening for connection to said conduit on the outlet side of said valve, an expansible contractible hollow member responsive to changes in barometric pressure, a spring operatively connecting said hollow member to said lever mechanism for exerting force on said lever mechanism tending to open said valve in accordance with decrease of barometric pressure, and means to connect positively said hollow member to said lever mechanism upon predetermined decrease of barometric pressure so that said hollow member acts directly upon said lever mechanism to 'urge said valve toward open position for all further decreases of barometric pressure.

11. In an aircraft carried heating apparatus having an air supply conduit leading from the extericr of and with its inlet directed upstream of the aircraft, a control device comprising a casing having a chamber with an open side, a pressure sensitive diaphragm sealing said open side, a butterfly type valve in said conduit, a shaft extending diametrically across said conduit and supporting said valve, said valve having its center plane offset in the direction of flow and from the longitudinal centerline of said shaft so that air pressure on said valve will tend to close said valve and compensate for variation of air pressure on said valve, said chamberhaving an aperture communicating with said conduit on the outlet side of said valve to subject said diaphragm to aircraft speed created air pressure, a lever carried by said casing and having a fulcrum and overlying said diaphragm, a thrust member operable to transmit movement of said diaphragm to said lever, a crank arm on said shaft extending away from said lever when said valve is in wide open position, a link connected to said lever and extending and connected beyond said shaft to said crank arm so that movement of said valve toward closed position is decelerated for equal increments of movement of said link, guide means cooperable with said thrust member, an evacuated hermetically sealed metal bellows overlying said lever, means adjustably supporting said bel- Ws at one end, the other end of said bellows having operative positive engagement with said lever intermediate said thrust member and said fulcrum, a spring in said bellows tending to move said lever in opposition to pressure increase in said chamber upon decrease in barometric pressure, a second evacuated hermetically sealed metal bellows overlying said lever, means adjustably supporting said second bellows at one end, the other end of said second bellows being positioned for operative positive engagement with said lever intermediate said thrust member and said first-named bellows, and a spring in said sec ond bellows and operable upon predetermined decrease of barometric pressure to expand said second bellows into positive engagement with said lever and tending thereupon to act with said first-named spring to accelerate the rate of opening movement of said valve upon continued decrease of barometric pressure.

12. In an aircraft carried heating apparatus having an air supply conduit leading from the exterior of and with its inlet directed upstream of the aircraft, a control device comprising a casing having a chamber with an open side, a pressure sensitive diaphragm sealing said open side, a butterfly type valve in said conduit, a shaft extending diametrically across said conduitand supporting said valve, said valve having its center plane oifset in the direction of flow and from the longitudinal centerline of said shaft so that air pressure on said valve will tend to close said valve and compensate for variation of air pressure on said valve, said chamber having an aperture communicating with said conduit on the outlet side of said valve to subject said diaphragm to aircraft speed created air pressure, a lever carried by said casing and having a fulcrum andover lying said diaphragm, a thrust member operable to transmit movement of said diaphragm to said lever, a crank arm on said shaft extending away from said lever when said valve is in wide open position, a link connected to said lever and extending and connected beyond said shaft to said crank arm so that movement of said valve toward closed position is decelerated for equal increments of movement of said link, guide means cooperable with said thrust member, an evacuated hermetically sealed metal bellows overlying said lever, means adjustably supporting said bellows at one end, the other end of said bellows having operative positive engagement with said lever intermediate said thrust member and said fulcrum, a spring in said bellows tending to move said lever in opposition to pressure increase in said chamber upon decrease in barometric pressure, a second evacuated hermetically sealed metal bellows overlying said lever, means adjustably supporting said second bellows at one end, the other end of said second bellows being positioned for operative positive engagement with said lever intermediate said thrust member and said first-named bellows, a sprin interposed between said second bellows and said lever, and a spring in said second bellows and operable upon predetermined decrease of barometric pressure to expand said second bellows against the force of said interposed spring to urge said valve toward open position against the pressure in said chamber and with an increasing compressive force of said interposed spring, said second bellows spring acting to move said second bellows into positive engagement with said lever upon a predetermined further decrease of barometric pressure and upon predetermined pressure in said chamber and tending thereupon to act with said first-named spring to accelerate the rate of opening movement of said valve upon continued decrease of barometric pressure.

13. In an aircraft carried heating apparatus, means forming an air heating chamberfor supplying heated air to a point of use, means forming a combustion chamber in heat exchange relation to said heating chamber, an atmospheric air inlet duct leading to said combustion chamber from the exterior of and directed upstream of the aircraft, means to supplyfuel to said combustion chamber at a substantially constantrate,

an 5 air. flow regulating valve in said duct anterior to-said-lsupply chamber, alcasingjhavinga pressure: chamber with anopen side,- a pressure sensitive diaphragm sealing said open side, a conduit establishing communication between said pres,-. sure chambereand-saidair supply chamber to subject said diaphragm to aircraftspeedcreated-air;

pressure; lever mechanism housed'insa-id casing and: operatively connecting said diaphragm to; said." valve: to movesaid valve toward closed position uiaonaircraft speed, created air pressure; increase in saidpressure chamber, barometricactuating means in said casing and-operativelycon-nectedto said lever mechanism to move saidvalve towardopenposition upon decrease of barometric pressure, and a heated air supply duct leadingirom said heating chamber anddischarging iritov said casing to heat said levermechanism.-

14. In an aircraft carried heating apparatus, means forming an air heating chamber for supplying heated air-to a point of use, a combustion chamber in heat exchange relation to said heating chamber; anatmospheric air inlet duct leading'tosaid combustion chamber from the exteriorof' and-directed-upstream of the aircraft, means to-suppl'y fuel to'said combustion chamber at a substantially constant rate, said inlet duct having means forming an air supply chamberfeedingsaid-combustion chamber, an air flow regulatingvalve in said duct anterior to saidsupply chamber, a casing having a pressure chamber with an openside, a pressure sensitive diaphragm sealing said open side, a conduit establishing communicatiorr'between; said pressure chamber andsaid air supply chamber to subject said diaphragm to aircraft speed created air prwsure,

lever mechanism housed'in said casing and operatively connecting said diaphragm to said valve tomove said'valve toward closed position upon aircraft speed created air pressure increase in said-pressure-chamber, and barometric actuating means in said=casing and operatively connected to said lever mechanism to move said valve toward=open-position upon decrease of barometric pressure.

15. In a vehicle carried heating apparatus,- means-forming a combustion chamber having an air-supply ductwith its inlet directed toward the directionof vehicle travel and extending from the-exterior of the vehicle, a-butteri'ly type valve member' in said'duct, a shaft'extending diametrically across said ductand supporting said valve member, said valve member having its center plane offset in the direction of flow through said duct and 'from thellongitudinal center line of said shaft so that air pressure on said valve member willztendtto close said valve member and to compensate-ion variation of air pressureon said valve member, means. responsive to vehicle speed created. air. pressurein said duct on the outlet side of: said: valve member, and means operativelyconnecting said: responsive means to said valvemember to move said valve member towardclosed position. with increase in vehicle speed.

16 In an aircraft carried heating apparatus, means. forming a combustion chamber having an air. supply duct with-its inlet leading from the exterior. of; the aircraft and directed toward thedirection. oil aircraft travel and into the aircraft air stream, a valvecontrolling flow through said duct, means responsive to aircraft air speed, means operatively connecting said responsive means tosaid valve-to move saidv-alve toward;

closed position with increase in airspeed, and barometric means-operatively connected to said valve and tending to open said valve with increase in altitude and in oppositionto-said responsive means.

17'. A control device, comprising a conduit membene valve member pivotally supported in said; conduit, member and operable to regulate flow therethroush, a lever arm rigid with said valve. member, a casing mountedlon said conduit:

member, a diaphragm cooperable with a wall of saidicasing. to ,forma pressure chamber, a lever pivoted onrsaid casing and operatively connected to:said.:ar1n tomove said valve member, a thrust. member, connecting said diaphragmto said lever such thatpressure increase-in said chamber will urge said valve member toward closed position, means. for communicatively connecting said chamber tothe' interior of said conduit member on-the outlet side of said valve member, a plurality or sealed metal-bellows supported by said casingand-responsive to changes in pressure external-to said chamber, said bellows being positioned on the-opposite sideof said lever from said diaphragmand between the lever fulcrum and said-thrust member, and'a thrust member operativel'y connecting said bellows to said lever such'that increase in pressure on said bellows will urge said valve member toward closedposition, said'bellows individuallybecoming effective in successive ranges at successive predetermined reduced-pressures and being positioned and arrangedto urge said valve member toward open-position-upon external pressure reduction, saidbellows acting cumulatively on said lever suchth'atfor a given increment of pressure reductionthere'is in each-succeeding range of pressure reduction an increased increment of lever -movement;

18-; A control device, comprising a conduit member, a generally elliptical valve member in said'concluit; member and controlling flow therethrough, a shaft pivotally supporting said valve member and projecting from said conduit memb'er,yan arm rigidly secured on an external end of saidshaft; ahousing member enclosing said arm, aclosed casing mounted on said conduit member, said casing and said housing member having registering openings, a. link pivoted to said armandq extending through said openings into saidgcasing, a lever in said casing extending transverse-to said'link and pivotally secured thereto, a; diaphragm cooperable with an interior wall of; said casingto form a; pressure chamber, a thrust member connecting said diaphragm to saidlever such as to move said valve; member toward closed position upon pressure increase in said-chamber; a plurality of bellows members in saidcasing-positioned between a wall of said casing and -saidlever, said bellows members engaging saidlever between the lever fulcrum and said-thrust member and being positioned on the oppositeside; of said lever from said diaphragm, s-aidbellows-members being positioned and adjusted for sequential operation on said lever thereby to provide a predetermined variation in theforceapplied-to said lever in opposition to said diapliragm, said' casing having an opening to subjectsaid bellows members to external pres- I9. A control" device; comprisinga conduit member, a generally elliptical valve member in said conduit member and controlling flow theretnrcugh, a shaft pivotally supporting said valve member and projecting from said conduit member, an arm rigidly secured on an external end of said shaft, a housing member enclosing said arm, a closed casing mounted on said conduit member, said casing and said housing member having registering openings, a link pivoted to said arm and extending through said openings into said casing, a lever in said casing extending transverse to said link and pivotally secured thereto, a diaphragm cooperable with an interior wall of said casing to form a pressure chamber, a thrust member connecting said diaphragm to said lever such as to move said valve member toward closed position upon pressure increase in said chamber, a plurality of bellows members in said casing positioned between a wall of said casing and said lever, said bellows members engaging said lever between the lever fulcrum and said thrust member and being positioned on' the opposite side of said lever from said diaphragm, said bellows members being positioned and adjusted for sequential operation on said lever thereby to provide a predetermined variation in the force applied to said lever in opposition to said diaphragm, said casing having an opening to subject said bellows members to external pressure, means for communicatively connecting said pressure chamber to the interior of said conduit member on the outlet side of said valve member, and means for heating said housing member.

20. A control device, comprising a conduit member, a butterfly type valve member in said conduit member, a shaft extending diametrically across said conduit member and supporting said valve member, said valve member having its center plane offset in the direction of flow through said conduit member and from the longitudinal centerline of said shaft so that fluid pressure on said valve member will tend to close said valve member and to compensate for variation of fluid pressure on said valve member, means responsive to variation of fluid pressure in said conduit member on the outlet side of said Valve member, means operatively connecting said responsive means to said valve member such as to urge said valve member toward closed position upon pressure increase, means responsive to static pressure external of said conduit member, and means operatively connecting said last-named means to said valve member such as to urge said valve member toward open position upon decrease of static pressure.

21. In a vehicle carried heating apparatus, means forming a combustion chamber having an air supply duct with its inlet directed toward the direction of vehicle travel and extending from the exterior of the vehicle, a valve controlling flow through said duct, means responsive to vehicle speed created air pressure in said duct, means operatively connecting said responsive means to said valve to move said valve toward closed position with increase in vehicle speed, and barometric means operatively connected to said valve and tending to open said valve with increase in altitude and in opposition to said responsive means.

EARNEST J. DILLMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 16,796 Keith Nov. 22, 1927 154.744 Brown Sept. 8, 1874 306,314 Beechey Oct. 7, 1884 427,516 Knickerbocker May 6, 1890 497,295 Acton May 16, 1893 1,461,520 Forman July 10, 1923 1,551,908 Prouty Sept. 1, 1925 1,562,663 Strong 1 Nov. 24, 1925 1,926,069 Sutton Sept. 12, 1933 1,958,023 Smith May 8, 1934 2,063,477 Young et al Dec. 8, 1936 2,112,391 Anxionnaz Mar. 29, 1938 2,212,606 Klinker Aug. 27, 1940 2,264,869 Beardsley Dec. 2, 1941 2,270,659 Meyn Jan. 20, 1942 2,313,149 Jacobson Mar. 9, 1943 2,314,089 Hess et a1 Mar. 16, 1943 2,364,214 Hess et a1 Dec. 5, 1944 2,388,669 Baker Nov. 13, 1945 2,388,970 Hess Nov. 13, 1945 2,403,186 Leslie July 2, 1946 2,418,566 Arnhym Apr. 8, 1947 FOREIGN PATENTS Number Country Date 2,316 Great Britain June 1, 1876 419,920 Great Britain Nov. 21, 1934 501,138 Great Britain Feb. 22, 1939 OTHER REFERENCES McAdams, Heat Transmission, second edition, McGraw-Hill Book Co., New York, 1942, chapter 5, page 119, formula 8a.. 

